Doug Baldwin popped a bottle of apple cider — he doesn’t drink alcohol — in celebration before Thursday’s press conference began in Renton.

Flanked by general manager John Schneider and coach Pete Carroll, the Seahawks formally announced a deal with Baldwin that can keep him in Seattle through 2016. He’ll play 2014 on a second-round tender, then be on a two-year extension after that. His guaranteed money is $8.5 million, with the deal reportedly worth at least $13 million total.

“Nothing changes for me,” Baldwin said. “I signed my name to a piece of paper. A piece of paper does nothing for me.”

The Seahawks previously placing a second-round tender on Baldwin, who was a restricted free agent, that left him three options: sign the tender and play for $2.187 million this season, sit out and wait until he became an unrestricted free agent in 2015, or work out a new deal with Seattle.

He was able to add an extension to the tender offer.

Baldwin’s 50 catches in 2013 were second on the team to departed Golden Tate. Since joining the Seahawks as an undrafted free agent in 2011, Baldwin has become an important part of not just the receivers group, but also of the team as a whole. His nickname of “Angry Doug Baldwin,” ADB for short, started at Stanford and followed him to the Seahawks, where he has become the poster child for their self-imposed underdog status.

Bringing back Baldwin means the Seahawks have signed their core to extensions during the offseason.

Defensive lineman Michael Bennett, cornerback Richard Sherman, free safety Earl Thomas and now Baldwin have agreed to contracts that can keep them all with Seattle until at least 2016.

Baldwin said there were two reasons he came to the Seahawks as an undrafted free agent in 2011.

First, Schneider had sent him a hand-written letter after the draft explaining why he thought Baldwin would be a fit in Seattle.

Second was his Stanford pal Sherman, who often refers to Baldwin as his son, though they are more like brothers.

Schneider and Carroll both lauded Baldwin’s work ethic, ability to be clutch and the attitude they say epitomizes what the organization wants to be about.

“Act like a pro and act like a champ every single day, which is what this individual does,” Schneider said.

According to Carroll, Baldwin will be playing split end this year after mostly playing as the slot receiver last season. Baldwin also threw his hat into the punt returner mix Thursday, though he said he didn’t want to lose out on being a blocker on punt returns.

ESPN’s John Clayton reported Baldwin turned down a four-year, $20 million offer. Baldwin did not address that specifically, but said this deal, which they verbally agreed to around 8:30 p.m. Wednesday before signing Thursday afternoon, allows him and the team flexibility.

“I get the security and when I come up again, I’ll be young,” Baldwin, 25, said.

The competition at wide receiver is heightened this fall. The Seahawks used their top pick in the draft to select wide receiver Paul Richardson and took Kevin Norwood in the fourth round. Schneider told Baldwin during Super Bowl week in New York, when the team was first having draft meetings, that they were likely to pick a couple wide receivers. Baldwin said he was ecstatic to hear that.

“He just said, ‘Keep bringing them in,’” Schneider said.

Baldwin also pointed out this is not the end for him, so he did not want to dwell on it or make it much of a big deal. He was even hesitant to have a press conference.

“To me, this is just part of the process,” Baldwin said. “I’m not retiring. I’m not in Canton (Hall of Fame), and that’s the ultimate goal.